By Margi Jenks

When I accepted the interpreter job at the Crater of Diamonds State Park, I had driven past the Park on Interstate 30, but I had never visited the park itself. So, before I moved here, I looked at Google Earth, Mapquest, and the State Park website to see what my new home was going to look like.  None of those views showed me anything that matched my mental picture of a crater.  I had visited Crater Lake National Park when I lived in Oregon.  It is an amazing deep hole filled with glorious blue water in the top of a tall mountain.  I had also seen pictures of the craters on the moon when the astronauts landed there in the 1970’s.  But, the fairly flat surface of the Crater of Diamonds mine area that I saw on the maps and in the pictures did not fit either of those two pictures of craters that I carried around in my mind.

I’ve always said that the key to enjoying the study of rocks, geology, is having a good imagination.  As I found out when I finally pulled into the State Park, the mine area really is as flat or slightly rolling as I had seen in the aerial photos and the pictures.  But, the flatness of the present mine area is not the reason that the word “crater” is part of our park’s name.  Back, about 100 million years ago, this part of Arkansas was at the edge of the ocean.  A volcano erupted at that ocean edge, and its center is our present mine area.  This eruption was very explosive, so explosive that it blew a hole (or crater) in the ground surface.  Geologists believe that this type of eruption, which forms a type of volcano that we call a “maar” is even more explosive than the eruption that blew a hole in the side of Mt. St. Helens in the state of Washington.  The frothy lava that this type of eruption creates turns into ash as it is blown out of the ground.  The ash cloud from that eruption, like the ash cloud formed by the recent eruption at Mt. Redoubt in Alaska, has so much velocity that the resulting ash cloud may reach miles into our atmosphere.  However, what goes up almost always comes down, and at some point that ash cloud had so much ash in it that it collapsed and fell back into the crater, filling it up with ash and bits of lava. 

Luckily for us, that ash cloud contained diamonds, which had formed with the lava deep in the Earth’s crust.  Geologists believe that this type of lava is formed as deep as 100 miles down in our planet’s crust.  So, when the ash cloud collapsed, the diamonds in that cloud fell back into that crater along with the ash and lava.  In the period of time between the end of that eruption and the present, the forces of water and erosion have washed away any small rim that might have formed around our volcanic crater.  But, the exploration of this diamond deposit, in order to understand its size and value, has shown that our crater is still there below the surface.  It is shaped somewhat like a martini glass.  Therefore, the word “Crater” in our name, Crater of Diamonds State Park, is exactly where it should be, because we are lucky enough to have a volcanic crater full of diamonds.

My source for this information is an excellent 1999 article written by J. Michael Howard, of the Arkansas Geological Commission, titled “Summary of the 1990’s Exploration and Testing of the Prairie Creek Diamond-bearing Lamproite Complex, Pike County, Arkansas, with a Field Guide”.  This article was published  in the Arkansas Geological Commission Miscellaneous Publication 18D, Contributions to the Geology of Arkansas, Volume 4. 

Field Last Plowed:  April 23, 2009

Diamond Finds for April 13 - April 26, 2009 (100 points=1 carat)

April 14 - Alice Hubbard, 8 pt. white; David Anderson, Kent City, MI, 2 pt. white; Denis Tyrrell, Bismarck, AR, 3 pt. white, 4 pt. white, 7 pt. brown, 9 pt. white, 46 pt. white

April 15 - Lynda Williams, Bebee, AR, 2 pt. yellow

April 16 - Denis Tyrrell, Bismarck, AR, 7 pt. white; Lloyd Kirkland, Centerville, MS, 10 pt. brown; Loran Barnes, Benton, AR, 6 pt. white; Carrie Hebert, Franklin, LA, 5 pt. white; Melinda Hebert, Franklin, LA, 5 pt. white; Alaina Hebert, Franklin, LA, 6 pt white

April 17 - Claud Dill, Murfreesboro, AR, 17 pt. white, 7 pt. white; Vincent Dolunt, East Point, MI, 26 pt. white; Bayleigh Wise, Lake Charles, LA, 16 pt. white; Thomas Houser, Bossier City, LA, 6 pt. white

April 18 - Denis Tyrrell, Bismarck, AR, 3 pt. white, 11 pt. brown; Linda Stewart, Latham, NY, 4 pt. white; Peri Hoffman, Oklahoma City, OK, 1.09 carat white

April 19 - John Choate, Jacksonville, AR, 6 pt. brown; Elijah Evans-Hughes, Hot Spring, AR, 6 pt. brown; D.J. Corliss, North Attlerboro, MA, 12 pt. yellow, 24 pt. white

April 20 - Denis Tyrrell, Bismarck, AR, 2 pt. white; 3 pt. white, 4 pt. white, 8 pt. yellow; Rodney Stewart, Tullahoma, TN, 9 pt. white

April 21 - Jeff Berry, Euless, TX, 19 pt. brown; David Anderson, Kent City, MI, 1.01 carat white

April 22 - Bill Moore, Murfreesboro, AR, 45 pt. white; Charlotte Jenkins, Carlile, AR, 21 pt. yellow; David Hinzie, White Bear Lake, MN, 22 pt. white

April 23 - Glenn Worthington, Springdale, AR, 7 pt. yellow; Shawn Calley, Murfreesboro, AR, 5 pt. white

April 24 - Scott Michelich, Morrow, OH, 5 pt. white; Rodney Stewart, Tullahoma, TN, 3 pt. white

April 25 - Thomas Houser, Bossier City, LA, 12 pt. white

April 26 - Wade Meyer, Danville, IA, 4 pt. white